The overall objective of this proposal is to continue the support at Vanderbilt University of an existing interdepartmental, multidisciplinary Reproductive Biology Research Center. The continuous support of the Center will maintain the efficiency of many population related projects now active at Vanderbilt and will permit development in a new area not presently represented. The research objectives of the Center include investigations on male reproductive physiology (sperm production, sperm biochemistry, sperm metabolism, sperm maturation, sperm capacitation, development male contraception, and neuroendocrine control of male sexual behavior), on female reproductive physiology (fertilization and implantation), and on reproductive endocrinology (reproductive hormones mechanism of action). Support is requested for an administrative core unit and seven core facilities (Histology/Photomicroscopy, Electron Microscopy, Tissue Culture, Protein Phosphorylation/Cyclic Nucleotide, Hormone Assay, Organic Chemistry/Prostaglandin, and Protein Chemistry).